So many good things about Flower Piano at the San Francisco Botanical Garden, but best of all, I think, is its celebration of plunkers, tappers, strokers, thwackers. This is where the piano student’s rubber meets the road ... but there’s no teacher glaring down at you. There are strangers only, and they don’t know your name, and they’re not going to put it on your permanent record that you don’t know how many flats there are in the key of A-flat.

As you probably read in Ryan Kost’s story about the project, in honor of the 75th anniversary of the San Francisco Botanical Garden, Sunset Piano has placed a dozen pianos in various glens, dells, hilltops and groves, and they’re all available for playing. There are scheduled performances, and we heard a very good one — Eric Chase played Mozart in the Redwood Grove — on Sunday, July 12.

But it was a whole other kind of unexpected pleasure to hear and watch what one’s fellow San Franciscans were doing. The typical adult, 40 years past those lessons, came strolling down a path, glimpsed a piano sitting in the middle of a knoll, and startled at the sight. He looked to the right, then to the left, then back to the instrument sitting silent, waiting to be touched. No one else was hovering nearby; no formal audience awaited his performance.

The stroller stopped, approached the instrument with tentative gait, hesitated, then sat down and very gently pressed a few keys. No one responded; no one seemed to be listening. After the first few notes, he played a little louder, surer. One piece, maybe two. Then a woman who looked as if she had trained singers in Moscow took the bench and played a Russian folk song. And next, a young Asian man from whose fingers rippled a perfectly flowing “Minute Waltz.” All Sunday afternoon, I heard only one “Heart and Soul,” banged out by a pair of schoolkids.

The low attention level of casual listeners was key, because there was no embarrassment in messing up. No one was trying to prove professional credentials, and no one was a failure.

A gentle event, sure. But for most amateurs, the chance to come out and play was like a romp through the meadows. Flower Piano is on until Monday, July 20, so you can catch it over the weekend.

At Saturday’s opening of Lava Thomas’ “Looking Back and Seeing Now,” a site-specific installation at the Berkeley Art Center, I noticed that the stream that runs beside the center wasn’t exactly gurgling. The center is tucked into a glen on Walnut Street. It’s a lovely spot that’ll be even better if it ever rains again.

Thomas’ show felt thirst-quenching. After the death of her grandmother, the artist discovered a forgotten photo album in a piano bench. In it were pictures of two women. With no one alive to identify them, Thomas couldn’t determine whether the women were relatives, but she found the faces arresting.

She spent a year and a half drawing them, “listening to the news while I worked,” says her statement. “As reports of brutality against black people streamed relentlessly from my computer, the defiance and sadness in the women’s eyes seemed poignant and timely.”

The two portraits are hung facing each other. In the space between them, hanging from the center ceiling, are 196 tambourines, some with their surfaces covered in black, some covered with mirrors, many covered with prints of the eyes from the portraits. As she worked on the portraits, writes Thomas, the gazes of the women seemed to focus on something joyful emerging, “and the work began to speak to me of transcendence and possibility.”

The movement of people walking around the room causes air currents that move the tambourines very slightly, creating an ethereal effect. The artist had chosen the tambourines because the instrument was used widely in protest marches and in African American churches.

Awestruck gallery-goers leaned in close to examine the finely wrought drawings, then moved around the periphery. And then went outside on a beautiful afternoon to sit on benches amid the greenery, to enjoy wine and snacks, to greet old friends and to talk about art.